1. Field of the Invention
The present invention relates to transmissions, and more particularly, to an infinitely variable ratio transmission.
2. Description of the Related Art
It is well known that a "transmission" is a mechanical device for transmitting power from a power source, such as an automobile engine or electric motor, to an output shaft or driven member, such as an axle connected to the drive wheels of an automobile. The two basic types of transmissions are manual and automatic, each of which generally transfers power to the output shaft at a multiple of discrete gear ratios. In this regard, automobile transmissions are commonly available as two- to six-speed transmissions, each speed having a different ratio. For reasons well known to those of ordinary skill in the art, it is desirable to provide a transmission with an infinite number of gear ratios, instead of being limited to a specific number of gear ratios. These types of transmissions are commonly referred to as continuously or infinitely variable ratio transmissions (IVRT). There are numerous approaches in the prior art to providing an IVRT, some of which employ a planetary gear set having a carrier plate with a set of pinion gears rotatably attached thereto that are meshed between a sun gear and a ring gear, the operation of which is well known in the art. Some of these approaches that employ planetary gear sets attempt to achieve an IVRT by connecting the power source to the carrier plate through an input shaft and then using some type of mechanism to apply a braking force to the sun gear. Sample types of braking mechanisms used to slow down the sun gear include belt and pulley arrangements, torque converters, gears, clutches, pumps, and motors, or a combination thereof. As more fully explained below, the IVRT of the present invention represents an improvement over IVRTs disclosed in the prior art.